Bharath, I am probably talking out of my orifice, but this isn't wood welding as I understand it. 'Normal' practice is, I seem to recall, based on radio waves (UHF?) to melt the cellular structures in two adjoining faces?
It was so esoteric - and costly - I never saw the need to investigate further. Incredibly, I think it was Jacob, in one of his few non-****-stirring moments who described it. I know. Hardly credible, but that's what I remember...